Judging by a quick scan of Newegg USA, G.SKILL is pretty much alone in bringing 8GB DIMMs to speeds above DDR4-3733. They already have a 2x8GB kit in the DDR4-4000 and DDR4-4133 ranges, but they're now introducing a 4x8GB kit into the DDR4-3866 classification. The chip is rated at CL18-19-19-39 when supplied with 1.35V. This is much higher voltage than slower sticks, but, as far as I can tell, pretty good at that speed. It also supports XMP 2.0 to automatically configure your BIOS, which is a bonus.
Granted, I cannot think of too many situations where four channels of high-bandwidth memory will give you any real benefits, apart from obviously a narrow list of overclocking record categories. Current DDR4-capable processors can do up to 16GB DIMMs. Personally, I'd tend to err on the side of slower, denser sticks of RAM. I'm more concerned about leaving everything I want in memory, versus any potential bottlenecks I might introduce in giving my CPU work. That's just me, though. If you have the need for high-bandwidth, quad-channel, DDR4 memory, then here you go.
Pricing has not yet been announced. That said, a 2x8GB DDR4-4000 (the next category up) of the same brand can be found for around $190 USD. 2x8GB DDR4-4133 (the next category above that) is about $220 USD. While those kits contain half the sticks, 2 vs 4, the new kit might be slightly cheaper per stick than these. That's just speculation, though, until retailers show their stock.
So what’s more important – CL
So what’s more important – CL timings or clockspeed?
RAM is complicated.
For decently programmed
For decently programmed applications, CL timings aren't really as useful now that CPUs prefetch effectively. That depends on developers aligning their memory in predictable ways (ex: arrays/vectors of structures vs linked lists) but yeah.
In general i would prioritize
In general i would prioritize clockspeeds but try to buy some of the ower CL available at your chosen clocks